如何提取 html 标签属性？

Question

I'm trying to develop my first RSS News Aggregator. I can easily extract the links, titles, publication date from the RSSItem Object. However, I'm having a hard time extracting the image from the feed Item. Unfortunately, due to my low reputation of SO I can't upload images, so instead of helping me extract the value of a src attribute of <img> , can u please show me how to get the value of the href attr of <a> tag. Highly appreaciated!!

Here's the string

<div style="text-align: center;"
    <a href="http://www.engadget.com/2011/07/10/element5s-mini-l-solarbag-brings-eco-friendly-energy-protectio/"></a>
</div>

---

Edit:

Maybe the whole title is wrong. Is there a way I can find the value using XPath?

Answer 1

Use HTMLAgilityPack as answered in this post:

How can I get values from Html Tags?

More information:

Html may not be well formed, hence we need another parser (other than XML one supplied in .net) that is more fault tolerant. That's where HTMLAgilityPack comes in.

Getting started:

1. create a new console application

2. right-click on references / manage nuget packages (install NuGet if you don't have it).

3. add html agility

A working example:

        using System;
        using System.IO;
        using System.Text;
        using HtmlAgilityPack;

        namespace ConsoleApplication4
        {
            class Program
            {
                private const string html = 
        @"<?xml version=""1.0"" encoding=""ISO-8859-1""?>
        <div class='linkProduct' id='link' anattribute='abc'/>
         <bookstore>
         <book>
           <title lang=""eng"">Harry Potter</title>
           <price>29.99</price>
         </book>
         <book>
           <title lang=""eng"">Learning XML</title>
           <price>39.95</price>
         </book>
         </bookstore>
        ";

                static void Main(string[] args)
                {
                    HtmlDocument doc = new HtmlDocument();
                    byte[] byteArray = Encoding.ASCII.GetBytes(html); MemoryStream stream = new MemoryStream(byteArray);
                    var ts = new MemoryStream(byteArray);
                    doc.Load(ts);
                    var root = doc.DocumentNode;
                    var tag = root.SelectSingleNode("/div");
                    var attrib = tag.Attributes["anattribute"];
                    Console.WriteLine(attrib.Value);
                }
            }
        }

Taking it further:

Get good at XPaths. Here's a good place to start.

http://www.w3schools.com/xpath/xpath_syntax.asp